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Objective: To test the null hypothesis was that there is no difference in the mean shear bond strength of indirectly bonded lingual brackets prepared with or without sandblasting prior to acid etching., Materials and Methods: Forty extracted human premolars were obtained and randomly divided into two groups of 20 each: group I (control), phosphoric acid and indirect bonding with Maximum Cure and Phase II (Reliance, Itasca, Ill); and group II, sandblasting with 50 μm aluminum oxide (Microetcher, Danville Engineering, Danville, Calif) prior to etching and indirect bonding. All products were used according to the manufacturer's instructions. Instron universal testing machine was used to apply an occlusogingival shear force directly onto the enamel-bracket interface at a speed of 0.5 mm/min. The groups were compared using unpaired Student's t-test. Kaplan-Meir survival plots and log-rank test were done to compare the survival distribution between the two groups., Results: Mean (SD) shear bond strength for group I was 13.17 (4.33) MPa and for the group II was 16.42 (5.41) MPa. Significant difference was observed in the bond strengths of the two groups evaluated (P = .048). However, the log-rank test demonstrated that clinical performance of the groups evaluated was not significantly different (P = .091). The adhesive remnant index (ARI) was significantly higher when using sandblasting prior to acid etching than in the control group (P = .011)., Conclusions: Intraoral sandblasting prior to enamel etching increased the bond strength of lingual brackets, but the clinical performance of the groups was not significantly different.

Objective: The purpose of this study was to evaluate shear bond strength of polycarbonate brackets bonded with or without the previous application of primer on their bases., Materials and Methods: Forty-six extracted bovine permanent mandibular incisors were obtained and randomly divided into two groups of 23 each: group 1 (control), 37% phosphoric acid and direct bonding with Orthoprimer (Morelli Orthodontic Products, São Paulo, Brazil) and Orthobond (Morelli Orthodontic Products); and group 2, Orthoprimer application on bracket base prior to conventional bonding. Polycarbonate maxillary central incisor brackets (Composite, Morelli Orthodontic Products) were used in this study. All products were used according to the manufacturer's instructions. An Universal Testing Machine was used to apply an occlusal shear force directly onto the enamel-bracket interface at a speed of 0.5mm/min. The groups were compared using Student's t-test., Results: Mean results and standard deviation (in MPa) for the groups were: group 1 - 5,81 (1,90); and group 2 - 6,09 (1,28). Significant difference was not observed in the bond strengths of the two groups evaluated (p=0.5601). The adhesive remnant index (ARI) did not indicate significant difference (p=0.617) between the two groups., Conclusions: These results indicated that primer application on polycarbonate bracket base did not result in increased bond strength., (Copyright © 2010 Società Italiana di Ortodonzia SIDO. Published by Elsevier Srl. All rights reserved.)

Introduction: The purpose of this clinical trial was to evaluate over a 12-month period the performance of a self-etching system (SEP) (Transbond Plus SEP, 3M Unitek, Monrovia, Calif) compared with a conventional multi-step system (TBXT) (Transbond XT, 3M Unitek)., Methods: Twenty-eight randomly selected patients were included in this study. They were randomly assigned to either the TBXT or the SEP group. A total of 548 brackets were bonded according to the manufacturer's instructions with Transbond XT adhesive paste (3M Unitek). The survival rates of brackets were estimated with the Kaplan-Meier analysis. Bracket survival distributions for bonding procedure, tooth location, dental arch, and patient sex were compared with the log-rank test., Results: The failure rates of the TBXT and SEP groups were 4.78% and 6.88%, respectively. No significant differences in the survival rates were observed between the bonding procedures (P = 0.311). When tooth location, dental arch, and sex were analyzed, only tooth location was significant. Posterior brackets were more likely to fail than anterior brackets (P = 0.013)., Conclusions: Both systems had low bond failure rates and are adequate for orthodontic bonding needs.

Aim: To compare the shear bond strength of stainless steel brackets obtained by 3 high-intensive light-emitting diode (LED) units with conventional halogen polymerization., Methods: A standard light-curing adhesive paste was used to bond brackets using different lamps and curing times. Eighty permanent bovine incisors were obtained and randomly divided into 4 groups. The first group was bonded using a high-output halogen lamp for 20 seconds, which served as a positive control. The other 3 groups were bonded with high-intensive LED curing devices for 10 seconds. After 30 minutes, a universal testing machine was used to apply an occlusal shear force directly to the enamel-bracket interface at a speed of 0.5 mm/minute. The groups were compared using Kruskal-Wallis test., Results: Mean results and standard deviations for the groups were: group 1 = 11.22 MPa (1.68), group 2 = 10.35 MPa (1.92), group 3 = 11.19 MPa (2.62), and group 4 = 11.82 MPa (2.09). No significant difference was observed in the bond strengths of the 4 groups evaluated (P = . 176)., Conclusions: Under the conditions of the present study, the high-intensity LED units with reduced light-curing time bonded brackets to etched tooth enamel as well as the halogen-based light-curing units.

The purpose of this in vitro study was to evaluate the influence of a new self-etching primer (Adper Prompt L-pop; 3M ESPE, St Paul, Minn) on shear bond strength of orthodontic brackets. Forty extracted human premolars were obtained and randomly divided into two groups of 20 each: group 1 (control), phosphoric acid + Transbond XT primer (3M Unitek, Monróvia, Calif) and group 2, Adper Prompt L-pop. Transbond XT adhesive paste (3M Unitek) was used in both groups for bracket bonding. All products were used according to the manufacturer's instructions. Instron Universal Testing Machine was used to apply an occlusal shear force directly onto the enamel-bracket interface at a speed of 0.5 mm/min. The groups were compared using Student's t-test. Mean results and standard deviation for the groups were: group 1 = 16.23 MPa (4.77), group 2 = 13.56 MPa (4.31). No significant difference was observed in the bond strengths of the two groups evaluated (P = .069). However, the adhesive remnant index was significantly less when conditioning the enamel with Adper Prompt L-pop compared with phosphoric acid (P = .0003). The results suggest no difference in bond strength whether a conventional etching and primer or Adper Prompt L-pop is used. The amount of adhesive on the enamel after debonding was significantly less when using Adper Prompt than when using phosphoric acid. These results indicated that Adper Prompt is potentially adequate for orthodontic bonding needs.

The aim of this study was to analyze the effect of a self-etching primer (Transbond Plus SEP, 3M Unitek, Monrovia, Calif), developed for orthodontic use, in the regularity and depth of adhesive infiltration in the enamel of human permanent teeth and to compare it with phosphoric acid using scanning electron microscopy (SEM). Thirty premolars were divided in two groups of 15 each: group 1(control)-phosphoric acid + Transbond XT Primer (3M Unitek) and group 2- Transbond Plus SEP. Transbond XT Adhesive Paste (3M Unitek) was used in both groups for bracket bonding. All products were used according to the manufacturer's instructions. Dental fragments were decalcified, and for micromorphologic observation of the adhesive penetration in enamel, the resin replicas, remnant at the base of the brackets, were covered with a thin gold layer and examined by SEM. Three calibrated examiners evaluated the photomicrographs and gave scores from 0 = without penetration to 2 = deep penetration. The Mann Whitney U-test (P < .0001) showed a statistical difference between the two groups. The results demonstrated that the SEP was more conservative and produced a smaller amount of demineralization and less penetration of adhesive in the enamel surfaces when compared with the conventional phosphoric acid system.

The aim of this study was to evaluate the influence of a self-etching primer (SEP) (Transbond Plus SEP, 3M Unitek, Monrovia, Calif) on shear bond strength of adhesive uncoated and precoated Victory brackets (3M Unitek). The sample group consisted of 23 patients, with four premolars each, equally divided in four different groups. Brackets were bonded in vivo by the same operator using a split-mouth random technique: group 1, 37% phosphoric acid + primer + composite + conventional Victory bracket; group 2, 37% phosphoric acid + primer + precoated Victory bracket; group 3, SEP + composite + conventional bracket; group 4, SEP + precoated bracket. After 30 days, premolars were extracted for orthodontic reasons and a Universal Instron Machine was used to apply an occlusal shear force directly to the enamel-bracket interface at a speed of 0.5 mm/min. The groups were compared using two-way analysis of variance. Mean results and standard deviation for the groups were: group 1 = 11.60 +/- 2.65 Mpa, group 2 = 9.79 +/- 2.71 Mpa, group 3 = 10.75 +/- 2.67 Mpa, and group 4 = 10.31+/- 2.70 Mpa. No difference was observed between the conventional etching and primer or SEP (P = .948). However, significant differences in bond strength were present between the uncoated and precoated brackets (P = .032). Considering the values required to withstand normal orthodontic forces (8-9 Mpa), it could be concluded that the SEP combined with adhesive precoated brackets showed adequate shear bond strength and may be suitable for clinical use.

The clinical performance of a glass ionomer cement for direct bonding of orthodontic brackets was compared with a composite resin routinely used in this procedure. Brackets were bonded, using both materials, in alternate quadrants of 16 patients of the Orthodontic Clinic of the State University of Rio de Janeiro. A total of 225 teeth, 112 in the glass ionomer cement group and 113 in the composite group, were tested. Bond failure frequencies were recorded for 12 months, and chi-square statistical test was carried out comparing the failure rates of the materials. The composite showed a statistically significant lower failure rate (7.96%) than the glass ionomer cement (50.89%), regardless of the dental arch tested. Although the glass ionomer cement presents important properties not observed in the composite, it is necessary to increase its cohesive strength to permit its clinical use for direct bonding of orthodontic brackets.

Forty-four brackets were bonded "in vivo" using cotton roll and rubber dam isolation. Maxillary and mandibular premolars, to be extracted for orthodontic reasons, were used in this study. After bonding, the teeth were retained in the mouth for at least 30 days. They were extracted using surgical elevators. After extraction, the teeth were secured in plastic rings using gypsum and kept in water for 7 days until debonding. A Universal Instron Machine was used to produce a shear force at a speed of 0.1 cm/min until each bracket was removed. No statistically significant differences for debonding strength were observed between the two types of isolation, nor between the buccal and palatal surfaces of the teeth. One hundred percent of the failures occurred at the bracket/composite interface.